The purpose of this contract is to provide bioanalytical chemistry resources to support NIDA's medications development program. New medications to be developed include new molecular entities as well as marketed drugs repositioned for the treatment of SUDs. Medication development is a long and complex process. NIDA supports every aspect of the medications development efforts including syntheses, pharmaceutics, bioanalytical chemistry, pharmacology, toxicology/toxicokinetics, pharmacokinetics (PK)/metabolism and clinical evaluations of potential medications through grants and contracts. This contract will serve as a centralized bioanalytical facility to support the preclinical PK/toxicokinetic studies, clinical pharmacology/PK studies and clinical trials for assessing the efficacy and safety of the study medications.